The Veterans Aging Cohort Study (VACS) is the largest clinical cohort of HIV infected Individuals (HIV+) in North America and includes in depth, longitudinal data on alcohol, multisubstance use (MSU), and outcomes over 7 years on 7,312 HIV+/- veterans at 8 sites (VACS 8). We have observed that among HIV+ drinkers, MSU is the norm (64% also use tobacco, opioids, or cocaine), but we do not know its implications for alcohol treatment. As the naturalistic observation study in the Consortium to improve OutcoMes in hiv/Aids, Alcohol, Aging, and multi-Substance use (COMpAAAS), we propose to build on the prior work of VACS to contribute to our consortium mission, to build and disseminate the evidence needed to optimize health care for HIV+ harmed by alcohol, MSU, HCV, and depression through coordinated, integrated, and externally validated observation, operations research (OR) modeling, and intervention studies. In this proposal we seek to characterize long-term (>10 year) longitudinal patterns and consequences of alcohol and MSU. This information that is essential to our mission and will inform all three U01 projects. We use this data to explore whether individually tailored health information on risks of alcohol and MSU increases motivation to change compared to generic advice to curtail alcohol use. To this end, we have developed and internationally validated the VACS Index (based on clinical biomarkers) and created a prototype VACS Index Calculator. While VACS analyses are essential to the COMpAAAS mission, our alcohol funding ends September 2011. Without additional follow up, our ability to characterize long-term longitudinal patterns and consequences of alcohol and MSU within important subgroups will be limited. Further, we hope to study contemporary patterns and consequences of alcohol and MSU among those initiating care since increased non medical use of prescription opioids (NMU) and changes in ART may be altering both patterns and consquences. Finally, Time Line Follow Back data (TLFB) are the gold standard for alcohol research but difficult to collect. By transitioning survey collection to a Web-Based format we will be able to collect TLFB data on alcohol and MSU and begin the transformation of VACS from a clinic cohort to an Interactive Web-Based Laboratory.